Door opens for migration debate

Gordon Brown has made another move to dominate the centre ground of British politics, the turf where the next election will be won and lost. As we report exclusively today, he will pledge to tackle immigration by tightening the language restrictions on immigrants. The rule that workers coming from outside the EU for high-skill jobs must be able to speak English will be extended to those coming for medium-skill jobs. The Prime Minister also will "consider" imposing it on all non-EU migrants.

If effectively implemented, the proposal could have a dramatic effect on immigration. It signals that Mr Brown is at least not trying to stifle debate about the issue. That was Mr Blair's preferred option. He closed down discussion on immigration very effectively, simply by accusing anyone who raised it of being "divisive".

The refusal of an honest and open debate has, up until now, been the hallmark of Labour policy. There was next to nothing on the topic in the party's last two manifestos. Labour has followed a policy of encouraging immigration to Britain from countries outside the EU, but has rarely, if ever, owned up to that fact. The result - a net inflow of around 200,000 people into Britain every year - means that the British electorate are the subject of a massive social experiment. Neither its advocates nor anyone else knows what the consequences of that experiment will be. British voters, however, have never been given any opportunity to register their endorsement or dissent from it.

Mr Brown's decision to introduce a policy with the explicit intent of restricting the flow of immigrants should change that, and we welcome it.

A national debate on the issue poses a potential dilemma for David Cameron and the Conservative Party. Mr Cameron has been so eager to distance himself and the Conservatives from accusations of being fixated on an outdated vision of Britain that he has been very reluctant to make clear statements about immigration. It is notable that in his article "What makes me a Conservative", in yesterday's Daily Telegraph, there was nothing about immigration - a topic near the top of voters' concerns.

The Prime Minister's latest initiative may force Mr Cameron into a more explicit statement of what he thinks Tory - and British - policy in this area should be. There are, of course, dangers here too. Mr Brown is trying to outflank the Opposition by seizing the initiative on immigration, and the moment Mr Cameron responds with a clear policy of his own, Mr Brown is likely to revert to Labour type, and attack it as reflecting "the same old Tory prejudice." But Labour is very vulnerable on the issue. The enormous increase in immigration to Britain over the last decade is almost entirely the consequence of Labour's conviction that it can only bring benefits to the country.

While most economists are far less sanguine than Labour ministers about the benefits of immigration, there is agreement on one point: it has the potential to change British society beyond recognition. Voters realise it, and want their concerns to shape the Government's policy. It seems that now, finally, there is a chance that they actually will.